Fenton与UV/Fenton降解DBP及BP的比较研究

Comparative study of DBP and BP degradation through Fenton oxidation or UV/Fenton oxidation

为了探讨高效去除环境中微量内分泌干扰物的方法,比较研究了Fenton氧化和UV/Fenton氧化2种高级氧化技术降解BP和DBP的条件与降解特性。结果表明,2种氧化体系在最佳反应条件为pH=4、Fe^2+/H2O2投加物质的量比1∶6、反应时间30 min时,BP和DBP的降解率均可达到93%以上;但在相同的降解率下,UV/Fenton体系所需氧化剂量分别比Fenton体系减少了1/4和2/3,且UV/Fenton体系降解产物达80%以上矿化。这表明与Fenton法比,UV/Fenton法为更高效的去除水中微量DBP和BP的方法。当DBP和BP混合共降解时,氧化剂投加量分别比单独降解减少了1/4和3/7,而其降解率均可达93%以上,表明两者间具有较好地协同促进作用。降解动力学分析表明,UV/Fenton(或Fenton)氧化降解BP和DBP的过程可分为·OH的快速生成、直接快速氧化阶段(反应的前5~10 min)和受Fe^3+/H2O2反应速率控制的缓慢降解2阶段,并可组合2个伪一级反应动力学模型较好地模拟整个反应过程,模型决定系数R2> 0. 99,均方根误差<0. 2。

The given paper is to make an exploration of the most efficient methods in removing the typical endocrine disruptors in the environment and the advanced oxidation rules and removal technics,such as the Fenton oxidation and UV/Fenton oxidation respectively to degrade the trace benzophenone (BP),dibutyl phthalate (DBP) and their mixtures in the sewage. The optimized conditions and features of BP and DBP degradation can be analyzed and compared in a profound way. The results of our analysis tend to indicate that the best degradation conditions can be stated as follows: the pH value is 4;the dosing ratio of Fe^2+/H2O2 is 1/6,whereas the reaction time serves as 30 min. On the above mentioned conditions,if the BP or DBP concentration serves as 1 mg/L,their degradation rates should be able to rise at a rate of over 93% either of the above 2 oxidation methods.Besides,the oxidation doses for BP and DBP degradation in the UV/Fenton oxidation can be made 2/3 or 1/4 lower than that in Fenton oxidation at the same degradation rate (over 93%) respectively. What is more,the BP and DBP degradation rate in UV/Fenton oxidation can be increased by 24. 8% and 14. 4%,respectively,than that in Fenton oxidation at the same dosage of oxidant (such as 50 μmol/L ferrous ion). What is more,it would be possible for over 80% degradation products to get mineralized entirely in UV/Fenton system. All the above research results prove that UV/Fenton method is more efficient than the Fenton one in the removal of trace DBP and BP in the sewage with the mixture of DBP and BP being co-degraded,The oxidation doses for BP and DBP degradation can be made equal to 1/4 (in UV/Fenton oxidation) and 3/7 (in Fenton oxidation) less than that of their degradation,respectively,in case their degradation rates were to be all over 93%. All the above research results suggest that the co-degradation results of BP and DBP enjoy a nice synergistic effect between the 2 stages. Besides,the degradation kinetics of BP and DBP also imply that the degradation process can be divided into 2 stages: At stage 1,the hydroxyl radical can be generated promptly and oxidized quickly and directly (during the first 5-10 min of the reaction). At stage 2,the slow degradation can be controlled by means of the reaction rate of Fe^3+/H2O2. And,what is the key,the entire reaction process can be simulated by joining the 2 pseudo-first grade reaction-kinetics models. The model correlation coefficient R2 is greater than 0. 99,with the RMS being less than 0. 2. Thus,it can be seen that we have made it possible to provide an effective method for degrading the trace DBP and BP simultaneously in the sewage.